I Have No Idea What It Is

I have no idea what this is supposed to be. I bought it in a "make offer" bargain bin from a game shop that was going out of business. It's 25mm, and it's from Citadel, but that's all I remember. It's some kind of science-ficiton cannon and two guys in vaguely Russian uniforms, but past that, your guess is as good as mine. (I say "vaguely Russian" because they look very Russian but have skulls where one would expect red stars.)

Probably the main comment I wanted to make was the base. The large rocks are pieces of decorative redwood bark, the groundwork itself is a mixture of Durham's water putty and kitty litter, and the base itself is a plastic lid from a jar of mixed nuts. The vegetation is dead stuff I found out in the yard. God knows what it is, except for dead.